Method of promoting diuresis



United States Patent 3,331,740 METHOD OF PROMOTING DIURESIS Anangur V. Subbaratnam, Chicago, Ill., assignor to Wilson & Co., Inc., a corporation of Delaware No Drawing. Filed Apr. 7, 1964, Ser. No. 358,064 4 Claims. (Cl. 167-65) This invention relates to therapeutic agents. More particularly, it relates to the compounds which are highly eifective as diuretic agents. Still more particularly, the invention relates to a method of inducing or promoting a high rate of urine flow and electrolyte excretion by administration of pharmacologically active dosages'of compounds falling in the category of derivatives of cinnamic acid.

In accordance with the present invention a compound or mixture of compounds selected from the class identifiable generally as substituted cinnamic acids and the water-soluble salts formed by the use of pharmacologically acceptable cations, either alone or in combination with known diuretics or saluretics or pharmaceutically acceptable carrier is administered to induce increased flow of urine and electrolyte excretion with minimal side effects.

Diuretics are important pharmaceuticals and are used extensively to augment the output of waste fluids and thereby to produce a significant loss of body weight, to reduce or eliminate edema or other symptoms usually associated with hypertension and the retention of an excessive amount of sodium ions in the body.

The classical diuretics, mercurials and xanthenes have become restricted in use because it is now recognized that they are toxic upon acute or chronic administration. These compounds also cause side eifects such as local inflammation, ecchymosis and plasma electrolyte imbalance.

In recent years, newer diuretics such as the substituted quiuazolinones, acetazol-amide, chlorthiazide, hydrochlorthiazide, have come into use. While such compounds do not have the side effects of the earlier diuretics, they do have disadvantages such as causing hypokalemia, hyperuricemia and metabolic acidosis. These disturbances of electrolyte baalnce are undesirable because they can result in listlessness, weakness, apathy and cardiac malfunction.

Another disadvantage of many of the diuretics currently in use is that they do not produce an increase in glomerular filtration rate or increase renal plasma flow as indicated by creatinine and para-amino-hippuric acid clearance rates, standard tests as described in Principles of Renal Physiology, Homer W. Smith (.1956), New York: Oxford University Press, whereas both actions are desirable for fast, elfective reduction in the quantities of water and salt which may be retained in the body tissues.

Now it has been discovered that compounds of the general formula wherein R represents a member selected from the group consisting of hydrogen, sodium, potassium, or other pharmacologically acceptible cation; R represents a member selected from the group consisting of hydrogen, an alkyl radical having up to 3 carbon atoms, i.e., methyl, ethyl and npropyl, isopropyl radicals, halogen radicals, phenyl radical, substituted phenyl radical and carboxyl radical;

R represents a member selected from the group consisting of hydrogen, halogen radical, an alkoxy radical containing 1 to 3 carbon atoms and an acyloxy group containing 2 to 6 carbon atoms; R represents a member selected from the group consisting of hydrogen, an alkyl radical containing 1 to 3 carbon atoms, an acyl radical selected from the group having 1 to 4 carbon atoms in the alkyl or alkene portion thereof; and R represents a member selected from the group consisting of hydrogen, halogen radical, nitro radical and an alkoxy radical containing 1 to 3 carbon atoms; R being halogen or nitro only when the R substituent is hydrogen, are effective non-toxic diuretics capable of inducing an increase in both glomerular filtration rate and renal plasma flow and may be administered alone or in combination with a pharmaceutically acceptable carrier, the proportions of which are determined by the solubility and chemical nature of the compound, the chosen route of administration, etc, to induce or promote diuresis in mammals without producing undesirable side etfects and without loss of etfectiveness upon prolonged administration.

Representative compounds useful for the purposes of this invention and falling within the generic structural formula indicated above are the free acids and watersoluble salts of nuclear substituted cinnamic acid, such as 3 methoxy 4 propionoxy cinnamic acid, 4 hydroxy 3 methoxy 5 chloro cinnamic acid, 4 hydroxy 3- methoxy 5 nitro cinnamic acid, 3 methoxy 4 acetoxy cinnamic acid, 3 ethoxy 4 acetoxy cinnamic acid, 3,5 dimethoxy 4 hydroxy cinnamic acid, 3,5- dimet-hoxy 4 acetoxy cinnamic acid, 3 methoxy 4- n-butyryloxy cinnamic acid, 4-hydroxy cinnamic acid, 3- methoxy-4-hydroxy-5-iodo cinnamic acid, 3-methoXy-4- ethoxy potassium cinnamate, 3-methoxy-4-acetoxy-alphamethyl cinnamic acid, 4-acetoxy cinnamic acid, 3-methoxy 4 crotonyloxy benzylidene malonic acid, 3- methoxy 4 isobutyryloxy cinnamic acid, 4 hydroxy- S-methoxy cinnamic acid and the substituted cinnamic acid compounds having a substituent in the acrylic acid portion of said compounds, such as alpha-methyl, alphabromo and alpha-(p-nitrophenyl) (-cis and trans).

The preferred groups of compounds for use as diuretics are the 3-alkoxy-4-acyloxy cinnamic acids, of which compound 3-methoxy-4-propionoxy (propionyloxy) cinnamic acid is a specific example believed to be a new compound.

In administering the compounds capable of inducing increased urine flow, such compounds may be adminis tered orally in the form of tablets or capsules, which forms may have water soluble coatings such as the synthetic gum carboxymethylcellulose, gelatin, and the like, and may contain starch, milk sugar, etc., as diluents. They may be administered sublingually in the form of soluble troches, etc. They may also be administered parenterally, that is intramuscularly, intravenously, or subcutaneously. For parenteral administration, the compounds may be used in the form of a sterile solution containing other solutes, for example, enough saline or glucose to make the solution isotonic, or in solution, suspension or emulsion in liquid carriers.

The following examples are given by way of illustration and are not to be construed as limitations upon the invention as may variations are possible Without departing from the scope and the spirit thereof.

Example I 3-methoxy-4-pr0pionoxy cinnamic acid may be prepared by acylation of ferulic acid with propionic anhydride. Ferulic acid may be prepared by the procedure of Vorsatz as described by I. W. Johnson in Organic Reactions, Vol. I, New York: John Wiley & Sons, Inc., 1960, Chap. 8, page 250. In order to obtain good yields of r 3 ferulic acid by this method, it is necessary to have the reactants, i.e., vanillin and malonic acid present in the 'mole ratio of 122.2. In preparing ferulic acid, a closable.

container is provided with a stopper carrying a calcium chloride guard tube. 2.52 kilograms of vanillin, 3.8 kilograms of malonic acid, 0.17 kilogram of piperidine and 8.3 liters of pyridine are introduced into the container. The mixture is stored for three weeks in a dark place protected from lightpThe liquid contents of the container are then poured with stirring into 8 liters of precooled, conwith an excess of propionic anhydride in the presence of dry pyridine and with suitable mechanical stirring. 388 grams of dried ferulic acid and 1430 grams of propionic anhydride, in a mole ratio of 1:5.5, are introduced into a vessel containing 160 milliliters of dry pyridine and provided with a reflux condenser and a mechanical stirrer. The mixture is heated under reflux for 6 to 10 hours with the internal temperature being maintained in the range of 90 C. to 100 C. The warm mixture is poured into 2 liters of Water containing 2 pounds of crushed ice. Initially, the product separates into a dark brown oil,

to 172 C. Thewhich upon standing from 4 to 6 hours is converted to a white solid. The white solid is separated from aqueous medium by centrifuging. The cake is then washed with water and filtered. Washing of the'product is continued until the product is free from any propionic acid. The product is then dried under vacuum at a temperature not exceeding 85 C.

The dried product is purified by fractionalcrystallization from dilute acetone. For this purpose, the dried product is dissolved in acetone in a weight ratio of approximately 1:20. The solution is mixed with charcoal and filter aids and filtered. The filtrate is concentrated on steam bath to a solution of weight ratio of approximately 1:13, and while warm, the concentrate is diluted with enough water to provide a weight ratio of solids to acetone-water solvent of approximately 1:21. The resulting solution is heated until it just reaches boiling stage and then allowed to cool down to room temperature. It is then stored for 2 to 4 hours in a cold place (about 5 C.). Crystallization occurs slowly. The first crystallizate, which is approximately 5% of the total yield, is removed by filtration as it generally contains a product having a melting point in the range of 215 to 220 C. After the separation of first crystallizate,

the filtrate is warmed on a steam bath until it turns just milky'and then is allowed to remain at room temperature for about 4 hours. After storing for 2 hours in a cold room (about 5 C.)a second crystallization occurs. The second crystallizate harvested from the dilute acetone solution is pure 3-methoxy-4-propionoxy cinnamic acid, M.P. 156 to 158 C. and shows a single spot in thin layer chromatography. The yield is approximately 85%.

Example 11 12: parts of ferulic acid, prepared according to the method described in Example I, are reacted with 50 parts of acetic anhydride and 3 parts of dry pyridine in accordance with the procedure described in Example I for the acid are suspended in 20 parts of methanol and are titrated with a 5% aqeuous solution of potassium hy droxide using a glass electrode until a pH of 8.3 is indicated. A pale yellow precipitate is separated by filtration. The filtrate is concentrated under an atmosphere of nitrogen, to a thick syrup. The syrup is brought into solution using methanol. Diethyl ether is added dropwise to the methanolic solution to achieve a faint turbidity. The cloudy solution is set aside in a cold place for crystallization. The crystalline product harvested is the potassium salt of 3-methoxy-4-acetoxy cinnamic acid, yellow in color and hygroscopic. It should preferably be stored in a closed container in a cold place, protected from light.

Example III 4-hydroxy-3-methoxy-5-chloro cinnamic acid is prepared by Vorsatzs method, described under Example I for the preparation of ferulic acid. The required aldehyde, 5-chloro vanillin is prepared by passing chlorine into a solution of vanillin and chloroform.

37.3 grams (0.2 mole) of 5-chloro vanillin, crystallized fom ethanol, M.P. 166 to 167 C., 45.75 grams (0.44 mole) of malonic acid, 120 milliliters of pyridine and 3 milliliters of piperidine are kept for three weeks at room temperature (20 C.), protected from light in a 7 closed container provided with a calcium chloride guard tube. Then the liquid contents are poured into 12 0 milli-- liters of cold concentrated hydrochloric acid. The 4-hydroxy-3-methoxy-5-chloro cinnamic acid precipitates from the solution. The precipitate is filtered, washed with a liter of 3% hydrochloric acid and cold water until neutral to litmus. The precipitate is dried in vacuum at a temperature not exceeding 85 C. The dried material crystallizes from dilute ethanol as glistening pale yellow needles, M.P. 245 to 246 C.

Example IV 12 parts of vanillin, 7 parts of p-nitrophenylacetic acid, 4 parts of pyridine and 40 parts of acetic anhydride are heated under reflux at approximately 150 C. bath temperature for 30 minutes. The reaction mixture is poured into 8 parts of cold concentrated hydrocloric acid with stirring. A yellow precipitate is formed after standing for ten minutes. The precipitate is dissolved in an excess of 7 solution.

The combined alkaline solutions are first acidified to pH 4.0 with acetic acid. A yellow precipitate separates and is collected by filtration. The precipitate is alpha-pnitrophenyl trans-3-methoxy-4-acetoxy cinnamic acid, M.P. 195 to 197 C., obtained in a yield of 6.7 parts. It crystallizes from hot ethyl acteate as yellow needles, M.P. 205 to 207 C.

The filtrates at pH 4, separated from the trans compound described above, and next acidified to pH 1.8 by the addition of concentrated hydrochloric acid. Now, an orange precipitate is obtained, M.P. C., which is the cis compound, viz, alpha-p-nitropheny1-cis-3-methoxy-4- acetoxy cinnamic acid; yield 1 part.

Evaluation of the product of Example I as a diuretic was made by the following test on a female dog of 8.0 1

the bladder, the residual urine evacuated, and the catheter left in situ.

20 nil/kg. body weight of a solution containing 2.5%

' 5 by weight of dextrose in physiological saline was given by gastric tube to provide a fluid load.

A forelimb vein was entered by means of an 18T gauge needle. A polyethylene venous infusion catheter was then passed into the vein through the needle, the needle being subsequently withdrawn and the catheter kept in place by means of adhesive strapping. A constant infusion of approximately 30 to 35 m1./hour dextrose-saline was maintained throughout the experimental period.

Urine was collected every hour for 3 hours. 25 mg./kg. 3-methoxy-4-propionoxy cinnamic acid was administered by mouth in capsule form. Urine was collected every hour thereafter for 3 hours. Urine samples were analyzed for sodium, potassium, chloride and bicarbonate levels. The following analysis shows the amount of sodium, potassium, chloride and bicarbonate in the urine before and after use of the product of Example I.

TABLE I Electrolyte Excretion em/min.) Hours Urine Flow (ml/min.) Na+ ID" 01- H;-

Medication-25 mgJkg. oral capsule product of Example I Medication-25 rug/kg. oral capsule product of Example I Evaluation of the product of Example H as a diuretic was made by the following test on a cat of 2.46 kilograms body weight. The cat was nem-butal anesthetized and the bladder and the femoral veins cannulated. An infusion was made to produce a saline load of 20 ml. per kilogram of weight. The product of Example H was dissolved in water and injected intraveniously. Thereafter saline was added in amounts to continuously balance the urine output.

The result of testing the product of Example 11 is given in Table II and the analysis of the electrolyte excretion, eqjmin. is given in Table 'III.

TABLE II Period Urine Flow Urine Flow Urine Flow (ml.[hr.) (ml/kg.) Ratio Control.-- 5 3. 5/k 1. 42 1. 00

m Hour 1 g 1. 34 O. 94

5 m Hour 2- 73k 2. 84 2. 00

5 m g. Hour 3-. 253k 8. 13 5. 75

5 mg. Hour 4-. 35. 57k 14. 4 10.1

5 mg. g. Hour 5.- 5 36. ()k 14. 6 10. 3

mg. g. Hour 6.. 35. 0 14. 2 10.0

TABLE III Electrolyte Excretion ew/min.) Period Na+ K+ Cl- H003 Evaluation of the product of Example III as a diuretic was made by the following test on a cat of 2.15 kilograms body weight. The cat was nembutal anesthetized and the bladder and the femoral veins cannulated. An infusion was made to produce a saline load of 30 ml. per kilogram of weight. The product of Example HI was suspended in oil and administered intramuscularly. Thereafter saline was added in amounts to continuously balance the urine output.

The result of testing the product of Example 111 is given in Table IV.

The product of Example IV was tested With I-Ioltzman male rats. The rats were tested in groups of four. An infusion was made to produce a saline load of 20 ml. per kilogram of weight. The product of Example IV was suspended in oil and administered intramuscularly.

The result of testing the product of Example IV is given in Table V.

TABLE V Urine Volume/5 Urine Flow Ratio hrs. (1111.) (ml/ g./5 hrs.)

Control Groug A 9. 5 1. 4 Control Group B 11.5 1.7 Test Group 20.0 2.9

I claim:

1. The method of promoting diuresis in animals which comprises administering pharmacologically active dosages of a compound selected from the group having the general formula wherein R represents a member selected from the group consisting of hydrogen, sodium and potassium; R represents a member selected from the group consisting of hydrogen, alkyl radicals having up to 3 carbon atoms, halogen radicals, the phenyl radical, nitro substituted phenyl radicals, and the carboxyl radical; R represents a member selected from the group consisting of hydrogen, halogen radicals and alkoxy radicals containing 1 to 3 carbon atoms; R represents a member selected from the group consisting of hydrogen, alkyl radicals containing 1 to 3 carbon atoms, acyl radicals selected from the group having 1 to 4 carbon atoms in the hydrocarbon portion thereof; and R represents a member selected from the group consisting of hydrogen, halogen radicals, and alkoxy radicals containing 1 to 3 carbon atoms; R being halogen only when the R substituent is hydrogen.

2. The method of promoting diuresis in animals which comprises administering pharmacologically active dosages of a nuclear substituted cinnamic acid wherein the nuclear substituents are hydroxyl in the 4 position, alkoxy r '7 in the 3 position, and halogen in the 5 position, said alkoxy group containing 1 to 3 carbon atoms. 3. The method of promoting diuresis in animals which comprises administering pharmacologically active dosages of 4 hydroxy-3-methoXy-5-chloro cinnamic acid. 7 4. An article comprising a water soluble coating composition enclosing a powdered compound of the general formula drogen, alkyl radicals having up to 3 carbon atoms, halogen radicals, the phenyl radical, 'nitro substituted phenyl radical, and carboxyl radicals, R5 represents a member selected from 'the group consisting of hydrogen, halogen radicals, and carboxyl radicals, R represents a member atoms; R represents a member selected from the group consisting of hydrogen, alkyl radicals containing 1 to 3 carbon atoms, acyl radicals, selected from the group having 1 to 4 carbon atoms in the hydrocarbon portion thereof; and R represents a member selected from the group consisting of hydrogen, halogen radicals, and alkoxy radicals containing 1 to 3 carbon atoms; R being halogen only when the R substituent is hydrogen.

, References Cited Marino el al., Chemical Abstracts, Subject Index, v01. 61, p. 657(s) and vol. 61, column -16671(c); abstracting Rassegna di Medicina Sperimentale, Vol. 10(4), pp. 194- 211 (1963).

ALBERT T. MEYERS, Primary Examiner. JULIAN S. LEVITT, Examiner.

LEROY B. RANDALL, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,331 ,740 July 18 1967 Anangur VG Subbaratnam It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 42, for "baalnce" read balance line 68, for "acceptible" read acceptable column 2, line 63, for "may" read many column 4, line 22, for "fom" read from column 6, line 5, for "30" read 2O column 8, lines 4 and S, strike out "and carboxyl radicals, R

represents a member atoms;" and insert instead and alkoxy radicals containing 1 to 3 carbon atoms;

Signed and sealed this 18th day of June 1968.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer 

1. THE METHOD OF PROMOTING DIURESIS IN ANIMALS WHICH COMPRISES ADMINISTERING PHARMACOLOGICALLY ACTIVE DOSAGES OF A COMPOUND SELECTED FROM THE GROUP HAVING THE GENERAL FORMULA 